I have a pretty bad stumble when I am running on the highway and punch it. I have a 350sbc with Performer RPM Air Gap manifold, Perf. RPM cam, and AVS carb. It runs good everywhere else, just when I am rolling along on the highway and floor it. It has a slight bog, but then it accelerates. I have fattened up both the primaries and secondaries, stiffer springs, changed the rods. Any suggestions??? Thanks in advance.

Stumble as you roll on the throttle or when you punch it?

punch

Secondaries might need to be a little fatter.....hmm. still got the carb kit Charlie? Edelbrock's are easy. keep playing. I did and ended up learning alot about carbs. Had a 750 EDEL on a 383 stroker that kept stumbling when I punched it. kept playing and It finally went away...it was fatter pri's and sec's...

I got .101 in the pri. and .098 in sec. That's as big as the kit has.

OH CRAP! try the ones that are smaller than the ones you had in there...
wow edel's are pretty simple. cant be much else...vaccum leak or timing...

What color primary springs do you have? Did using stiffer springs make a difference? What accelerator rod positions have you tried?

Right now it is in the highest hole on the accel pump lever and if I can remember correctly I have the blue springs in it. I am pretty sure there is no vacuum leak and the timing is 15 initial with 36 total and I have an adjustable timing box inside the car that I can adjust on the fly. I sprayed carb cleaner all around the engine while it was idling and the rpm's never changed.

hmmm....Ill have to try and find my list for the spring colors....